Inflatable balloon



FIG. 1 is a front perspsective view of the inflatable balloon showing my new design;

FIG. 2 is a front elevational view thereof, the rear being the same;

FIG. 3 is a top plan view thereof;

FIG. 4 is a left side elevational view, the right side being the same; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for an inflatable balloon, as shown and described. 